Over the years, the Matrix:festival has become more a series of events than an intensive celebration.

“We wanted to make it feel more like a festival,” Brigham said. “We shmushed it all down into an 11-day festival format” and “decided we wanted to throw a big old party.”

So in addition to the usual concerts, talks and exhibits, this year’s festival includes Saturday’s party.

“We wanted to make sure that we also had something fun and engaging for families,” Brigham said. “We have 12 hours of music happening in the library parking lot, with food trucks and craft brewers. … It is intended for families, young families with kids, young adults. …”

Block party entertainment kicks off about 10 a.m. with the local percussion group The Resonators, and performances by various groups continue until 11 p.m.

Among the more unusual performances is Pittsburgh-based Squonk’s “Cycle Sonic” at 4, 7 and 10 p.m.

Squonk does “steam punk-inspired performance art,” Brigham said. “It’s rock music … and they have built massive musical machines” that are powered by cycles, gear-driven and have no carbon footprint.

“It’s an all-original work of indie rock, electric bagpipes … a visual spectacle along with the all-original music.”

Also on the bill is American Opera, the brainchild of Michigander John Bee, who recently signed with Spartan Records and performed at the South by Southwest festival; and country-flavored Steve Armstrong and the 25-Cent Beer Band.

A craft beer tent, which opens at 3 p.m., will feature refreshments from the Midland Brewing Co., Mountain Town Brewing, Tri-City Brewing, Four Leaf Brewery and Forgotten Ciders. Admission to the beer tent is $1, with drink prices in the $4-$6 range.

Going on simultaneously will be the 51st annual Summer Art Fair, which is expected to draw about 100 vendors. Art fair hours are both Saturday and Sunday, 10 a.m. to 5 p.m., and admission is free.

Brigham said the number of vendors at the art fair has been relatively stable in recent years but “the major shift that we’ve seen … is that we have more regional craftsmen.”

In addition, the Friends of the Library book sale is open to the public Saturday from 10 a.m. to 4 p.m. and Sunday from 10 a.m. to 3:30 p.m. Sunday is “$6 Bag Day,” when attendees can purchase a grocery-sized bag of books for just $6. The sale will be held both inside and outside the library.